The 2004 International Headache Society (IHS) classification of headache disorders introduced the new category of probable migraine defined by the existence of all but one of typical migraine criteria. FRAMIG 3, the first nationwide population-based survey performed in France using the 2004 IHS classification, assessed the prevalence of probable migraine and compared its features and management with those of strict migraine. Of a representative sample of 10 532 adult subjects interviewed, 1179 subjects (11.2%) were diagnosed as having strict migraine and 1066 (10.1%) as having probable migraine. The criterion most frequently missing was typical headache duration (4–72 h) and most subjects with probable headache had shorter average headache duration. Migraine severity and disability, although lower than those noted in subjects with strict migraine, were significant in subjects with probable migraine and quality of life impairment was identical among the two groups of migraine sufferers. Strict and probable migraine, which have similar prevalence and impact on migraine subjects, deserve similar medical and therapeutic management.